/**
 * Copyright 2010 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hbase.client;

import java.io.IOException;
import java.util.Date;
import java.util.List;

/**
 * Exception thrown by HTable methods when an attempt to do something (like
 * commit changes) fails after a bunch of retries.
 */
public class RetriesExhaustedException extends IOException {
	private static final long serialVersionUID = 1876775844L;

	public RetriesExhaustedException(final String msg) {
		super(msg);
	}

	public RetriesExhaustedException(final String msg, final IOException e) {
		super(msg, e);
	}

	/**
	 * Datastructure that allows adding more info around Throwable incident.
	 */
	public static class ThrowableWithExtraContext {
		private final Throwable t;
		private final long when;
		private final String extras;

		public ThrowableWithExtraContext(final Throwable t, final long when, final String extras) {
			this.t = t;
			this.when = when;
			this.extras = extras;
		}

		@Override
		public String toString() {
			return new Date(this.when).toString() + ", " + extras + ", " + t.toString();
		}
	}

	/**
	 * Create a new RetriesExhaustedException from the list of prior failures.
	 * @param callableVitals Details from the {@link ServerCallable} we were using
	 * when we got this exception.
	 * @param numTries The number of tries we made
	 * @param exceptions List of exceptions that failed before giving up
	 */
	public RetriesExhaustedException(final String callableVitals, int numTries, List<Throwable> exceptions) {
		super(getMessage(callableVitals, numTries, exceptions));
	}

	/**
	 * Create a new RetriesExhaustedException from the list of prior failures.
	 * @param numTries
	 * @param exceptions List of exceptions that failed before giving up
	 */
	public RetriesExhaustedException(final int numTries, final List<ThrowableWithExtraContext> exceptions) {
		super(getMessage(numTries, exceptions));
	}

	private static String getMessage(String callableVitals, int numTries, List<Throwable> exceptions) {
		StringBuilder buffer = new StringBuilder("Failed contacting ");
		buffer.append(callableVitals);
		buffer.append(" after ");
		buffer.append(numTries + 1);
		buffer.append(" attempts.\nExceptions:\n");
		for (Throwable t : exceptions) {
			buffer.append(t.toString());
			buffer.append("\n");
		}
		return buffer.toString();
	}

	private static String getMessage(final int numTries, final List<ThrowableWithExtraContext> exceptions) {
		StringBuilder buffer = new StringBuilder("Failed after attempts=");
		buffer.append(numTries + 1);
		buffer.append(", exceptions:\n");
		for (ThrowableWithExtraContext t : exceptions) {
			buffer.append(t.toString());
			buffer.append("\n");
		}
		return buffer.toString();
	}
}